Security basics every startup should ship with

Security is treated as a later problem until the day it is not. The good news: a handful of basics prevent the majority of real-world incidents.

The essentials

• Put strict security headers in place (CSP, HSTS, frame protection)
• Validate and sanitize every input on the server, never trust the client
• Rate-limit sensitive endpoints to stop abuse and spam
• Keep secrets in environment variables, never in your code or git history
• Audit dependencies regularly and remove what you do not use

Build it in, do not bolt it on

The cheapest time to add security is while you build. Retrofitting it after launch costs far more and usually happens under pressure. Make it part of the definition of done.